DESCRIPTION: The goal of this project is to examine the relationship between nonword repetition and lexical knowledge in children with and without specific language impairments (SLI). Many studies have reported that children with normal language development (NLD) more accurately repeat nonwords with frequently occurring phonotactic patterns, presumably because children use phonological information drawn from over their lexicons to support repetition. Further, a number of studies have found a significant relationship between nonword repetition and standardized measures of receptive vocabulary in children with NLD. Researchers extended these studies to include children with SLI, and have consistently found that they repeat nonwords less accurately, but that they are sensitive to wordlikeness. While some studies reported that children with SLI show similar wordlikeness effects to children with NLD, others reported significant group by wordlikeness interactions, suggesting that they are more influenced. A potential problem is that those studies examining sensitivity to wordlikeness employed very different phonotactic frequency manipulations. Results for children with SLI differ further in that a number of studies have found no relationship between nonword repetition and standardized vocabulary measures. This may be due to low statistical power or perhaps an artifact of the vocabulary measures used, or possibly indicative of a fundamentally different path to lexical development. The purpose of this project is to examine how children with SLI extract phonological information from their lexicons and then use this information to support subsequent vocabulary acquisition, compared to children with NLD. A total of 80 children will participate in this three-year project, including 40 children with SLI, aged 4;0 - 6;0, and 40 age-matched children with NLD. Study 1 will examine how children with SLI extract phonological information from their lexicons by comparing them to children with NLD in four nonword repetition tasks in which different sources of phonotactic frequency are manipulated. Study 2 will directly examine the relationships between nonword repetition ability and both experimental and standardized measures of vocabulary knowledge. The outcomes of this project will inform our understanding of lexical and phonological development in children with SLI, and will provide valuable insights for the development of effective interventions. The proposed research will examine the relationship between phonological and lexical development in children with specific language impairments (SLI). These children have difficulty acquiring and using spoken language in spite of having all of the cognitive prerequisites that typically promote normal language acquisition. The proposed research will examine potential phonological processing deficits in young children with SLI in order to better understand the underlying causes of the disorder so that more effective remediation therapies can be developed.